Scientists say world on the verge of eliminating AIDS,but what of HIV?

Among those gains: antiretroviral drug combinations for women to prevent infection of their newborns; drugs to treat and prevent infection with HIV,the virus that causes AIDS,among adults; and evidence that voluntary male circumcision can reduce the risk of female-to-male transmission by 50 to 60 percent.

Today,HIV has become a chronic disease that,if treated appropriately,can be held at bay in a newly infected young adult for decades — if the patient adheres to the rigid daily drug regimen.

Ending the AIDS epidemic is likely to be far more complicated than ending most other epidemics. The AIDS conferences,which began in 1985 to boost morale and raise aspirations of people fighting AIDS,is now more of a conventions than scientific meetings. Rhetoric is plentiful,and separating it from fact is sometimes a challenge. Lobbying for more AIDS money is a given.

One obstacle is a failure to clearly define epidemic or what it means to have an AIDS-free generation. Definitions of terms may help determine how many billions of dollars the world devotes to the battle against AIDS. A failure to meet ill-defined goals could lead to public misunderstandings that limit investments.

To begin with,defining the word “epidemic” is difficult. The term is flexible and subjective. Even more elusive is determining what constitutes the end of an epidemic.

AIDS makes people deathly ill from problems like severe weight loss,swollen lymph nodes and a loss of critical immune cells that increases a person’s vulnerability to myriad other infections. But HIV infection can remain silent for several years before causing symptoms.

Some speakers defined an AIDS-free generation as the absence of people sick from the disease. But even if there is no one with AIDS,there will still be millions of HIV-infected people with us for a very long time. In those terms,HIV will likely be endemic until there is a cure. An AIDS-free generation,if it arrives,will live in a world where HIV very much remains a threat.

Bill Gates,whose foundation is spending billions on developing AIDS preventions,expressed skepticism that the world could soon end the AIDS epidemic by any conventional definition. “Unfortunately,we do not have the tools,and we need lots of new tools,” with a vaccine the ultimate preventive one,Mr Gates told the conference.

Many participants likened ending the AIDS epidemic to medicine’s successes against two other viral infections,smallpox and polio. But even Polio requires regular controlled public health efforts to stave off the disease,and it still is spread in Nigeria,Afghanistan and Pakistan. The conference participants who spoke of eradicating or eliminating AIDS failed to recognise that a vaccine was required to succeed against smallpox and polio.

US Secretary of State Hillary Rodham Clinton told the conference that her definition of an AIDS-free generation means “virtually no child anywhere will be born with the virus” by 2015. People who become infected “will have access to treatment that helps prevent them from developing AIDS and passing the virus on to others.”

Under Mrs Clinton’s definition,many people will continue to become HIV-infected,but not go on to suffer the myriad other infections and devastation caused by AIDS. But even if that goal is reached,millions will be living with HIV for a long time to come.